JP2002265454A - Benzimidazole derivative and curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a one-part type epoxy resin photo-setting resin composition having excellent preservation stability in the dark. SOLUTION: This curable composition is characterized as comprising a benzimidazole derivative represented by the general formula (I) and a polyfunctional epoxy compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel benzimidazole derivative and a curable composition, and more particularly, to an epoxy resin-based cured composition which is cured by light irradiation and heating.

[0002]

2. Description of the Related Art Hitherto, various photocurable compositions have been used for various uses such as coating materials, paints, inks, printing plates, resists, adhesives and the like. A) A composition comprising an acrylate and a photoradical generator. This reaction system is characterized by its excellent photocurability and the variety of (meth) acrylate combinations that can be used. However, the (meth) acrylate-based cured product has a large volume shrinkage at the time of photocuring, and generally has problems in adhesiveness and dimensional stability. Further, there is a problem that the photo-radical curing system is greatly affected by oxygen, polymerization of the surface is inhibited, and curability is poor. Furthermore, many (meth) acrylates used are highly irritating to the skin and have problems in handling.

A photocurable composition comprising a polyfunctional vinyl ether or an epoxy compound using a photoacid generator such as diphenyliodonium hexafluoroantimonate and triphenylsulfonium tetrafluorophosphate is also known as a cationic photopolymerization system. ing. This photocurable composition has characteristics of relatively small volume shrinkage, no polymerization inhibition by oxygen, and low skin irritation. However, the strong acid generated from the photoacid generator as described above corrodes the substrate in the electronics field,
Since there is a possibility that the insulation property may be reduced, the use thereof is limited. In addition, this reaction system
Although not inhibited by oxygen, it is largely inhibited by moisture and hydroxyl groups of the reaction system. Therefore, in such a photocuring system, removal of impurities, selection of a functional group, purity and the like are very important, and there is a problem that it is difficult to handle industrially.

As a photocurable composition which does not have the above-mentioned problems, an epoxy resin composition using a photobase generator is known (Japanese Patent Application Laid-Open No. 9-40750).
This system uses a photobase generator that generates imidazole by light when curing an epoxy resin excellent in mechanical strength and dimensional stability with an amine catalyst, and poses a problem when using imidazoles as a curing catalyst. It is intended to improve storage stability. However, the storage stability of the epoxy resin to which these photobase generators are added is not so high.

[0005]

The object of the present invention is to provide a cured product having excellent curing properties by releasing an organic base by light irradiation to act as a catalyst and then performing a thermosetting reaction. It is an object of the present invention to provide a liquid epoxy resin-based photocurable composition, and it is more difficult to store in a dark place than a photocurable resin composition using 2-nitrobenzyloxycarbonylimidazole of a similar type. An object of the present invention is to provide a one-pack type epoxy resin-based photocurable composition having extremely excellent stability.

[0006]

Means for Solving the Problems The present invention provides a novel compound represented by the following general formula (I) which is used for a one-pack type epoxy resin-based photocurable composition having a much better storage stability than before. Benzimidazole derivative,

[0007]

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(Wherein R 1 and R 2 may be the same or different and each represents a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a propyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert- Represents a butyl group, a pentyl group, a hexyl group, an alkyl group (having 7 or more carbon atoms), an alkoxy group, an alkenyl group, a cyano group, a nitro group, a phenoxy group, an aralkyl group or an aryl group; R3, R4, R5, and R6 may be the same or different and may be a hydrogen atom, a halogen atom, a methyl group, an ethyl group,
Propyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, alkyl (7 or more carbon atoms) group, alkoxy group, alkenyl group,
Represents a cyano group, a nitro group, a phenoxy group, an aralkyl group or an aryl group, and each of R3, R4, R5, and R6 may combine to form a ring, or a plurality of these rings may form a condensed ring; Is also good. And (B) a curable composition comprising a benzimidazole derivative represented by the general formula (I), which generates free benzimidazoles by light irradiation, and (B) a polyfunctional epoxy compound. A composition.

Further, the present invention provides (A) a benzimidazole derivative represented by the general formula (I) which generates free benzimidazoles by light irradiation, (B) a polyfunctional epoxy compound, and (C) a polyfunctional epoxy compound. Functional phenolic compounds,
A curable composition characterized by containing at least one compound selected from the group consisting of polyfunctional carboxylic acids, acid anhydrides and amine compounds, represented by the general formula (I) An N, N′-carbonyldibenzimidazole derivative represented by the general formula (II), which is an intermediate for synthesizing a benzimidazole derivative.

[0010]

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(Wherein R 3, R 4, R 5 and R 6 are the same as defined above)

The epoxy resin-based curable composition according to the present invention is characterized in that a benzimidazole derivative having a structure in which an amino group of a benzimidazole is blocked is used as a catalyst for a curing reaction as described above. In the case of a derivative having a structure in which the amino group of imidazole is blocked, the nitrogen atom at the 3-position of the imidazole ring has a strong basicity, and the reaction gradually proceeds before irradiation with light to generate imidazole, and the composition gels. Would. Therefore,
In the curable composition of the present invention, it does not act as a catalyst for the above reaction unless irradiated with light, and is stable, but benzimidazole which releases benzimidazoles by a photoreaction only by irradiating light It is constructed so as to have excellent storage stability by using a class derivative.

Hereinafter, N- (2-nitrobenzyloxycarbonyl) benzimidazole will be described as an example of a typical benzimidazole derivative used in the present invention. This compound has an amino group blocked. Since it is stable and has a weaker basicity of the nitrogen atom at the 3-position of the benzimidazole ring than the imidazole derivative, it does not act as a catalyst for the above-mentioned reaction unless irradiated with light. Therefore, an epoxy resin-based cured composition containing such a benzimidazole derivative has excellent storage stability, for example, unless stored in a dark place and irradiated with light. However, by photoirradiation, photodecomposition occurs according to the reaction formula of Chemical formula 6 to generate benzimidazole. Therefore, by subsequently heating the cured composition of the present invention, the benzimidazole produced by the above reaction exhibits an excellent catalytic action, and a cured product having excellent curing properties can be obtained.

[0014]

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In the present invention, in addition to the above-mentioned N- (2-nitrobenzyloxycarbonyl) benzimidazole, as is clear from the above-mentioned reaction formula, nitrobenzyloxycarbonyl which blocks the secondary amino group of benzimidazole is used. Any benzimidazole derivative having a structure that causes a redox reaction between the methylene group and the nitro group of the nitrobenzyl group of the residue and decarbonation can be used. For example, the nitro group of the nitrobenzyloxy group
Any of the 2-, 3-, and 4-positions may be used, and positions other than the nitro group may be halogen, methyl, ethyl, propyl, n-butyl, isobutyl, sec-butyl, t
It may be substituted by an ert-butyl group, a pentyl group, a hexyl group, an alkyl group (having 7 or more carbon atoms), an alkoxy group, an alkenyl group, a cyano group, a nitro group, a phenoxy group, an aralkyl group or an aryl group. In this case, the nitro group substitution position of the nitrobenzyloxy group is most preferably the 2-position. Further, the benzoimidazole derivative may be substituted with a group which is expected to have an effect of increasing the wavelength used in the photolysis reaction of the benzimidazole derivative and forms a ring by bonding to a benzene ring. The same can be said for the benzene ring unit on the benzimidazole group side.

The benzimidazole derivative used in the present invention is the following representative compound, N- (2
-Nitrobenzyloxycarbonyl) benzimidazole can be synthesized by the same method as that described above. Specifically, N- (2-nitrobenzyloxycarbonyl) benzimidazole is N, in the presence of a tertiary amine,
It can be synthesized by reacting N'-carbonyldibenzimidazole with 2-nitrobenzyl alcohol,
It can also be synthesized by reacting 2-nitrobenzyl chloroformate with benzimidazole.

Here, when comparing the synthesis method with the synthesis method, the intermediate carbonyldibenzimidazole has extremely high reactivity and does not generate an acid during the reaction. This is extremely useful compared to the fact that the mate generates hydrochloric acid during the reaction. In addition, when the intermediate is used, a certain R3,
By using an N, N'-carbonyldibenzimidazole derivative having R4, R5, R6 substituents, the substituents R1, R2 on the other 2-nitrobenzyl alcohol side can be obtained.
By variously selecting 2, it becomes possible to easily synthesize many kinds of benzimidazole derivatives,
The N, N'-carbonyldibenzimidazole derivative represented by the general formula (II) is a very useful intermediate.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The following compounds can be mentioned as specific examples of the benzimidazole derivative represented by the general formula (I) of the present invention. Among them, the substituent on the benzimidazole side is represented by R3 = in the general formula (I).
R6 and R4 = R5 are easier to synthesize. (I-1) N- (2-nitrobenzyloxycarbonyl) benzimidazole (I-2) N- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) benzimidazole (I-3) N- (5- Methyl-2-nitrobenzyloxycarbonyl) benzimidazole (I-4) N- (4-chloro-2-nitrobenzyloxycarbonyl) benzimidazole (I-5) N- (3-nitrobenzyloxycarbonyl) benzimidazole ( I-6) 1- (2-Nitrobenzyloxycarbonyl) -4-
Methylbenzimidazole (I-7) 1- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) -4-methylbenzimidazole (I-8) 1- (5-methyl-2-nitrobenzyloxycarbonyl)- 4-methylbenzimidazole (I-9) 1- (4-chloro-2-nitrobenzyloxycarbonyl) -4-methylbenzimidazole (I-10) 1- (2-nitrobenzyloxycarbonyl) -4-
Nitrobenzimidazole (I-11) 1- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) -4-nitrobenzimidazole (I-12) 1- (5-methyl-2-nitrobenzyloxycarbonyl)- 4-nitrobenzimidazole (I-13) 1- (4-chloro-2-nitrobenzyloxycarbonyl) -4-nitrobenzimidazole (I-14) 1- (2-nitrobenzyloxycarbonyl) -5-
Methylbenzimidazole (I-15) 1- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) -5-methylbenzimidazole (I-16) 1- (5-methyl-2-nitrobenzyloxycarbonyl)- 5-Methylbenzimidazole (I-17) 1- (4-chloro-2-nitrobenzyloxycarbonyl) -5-methylbenzimidazole (I-18) 1- (2-nitrobenzyloxycarbonyl) -5-
Nitrobenzimidazole (I-19) 1- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) -5-nitrobenzimidazole (I-20) 1- (5-Methyl-2-nitrobenzyloxycarbonyl)- 5-nitromethylbenzimidazole (I-21) 1- (4-chloro-2-nitrobenzyloxycarbonyl) -5-nitrobenzimidazole (I-22) 1- (2-nitrobenzyloxycarbonyl) -4,
5-dimethylbenzimidazole (I-23) 1- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) -4,5-dimethylbenzimidazole (I-24) 1- (5-methyl-2-nitrobenzyl (Oxycarbonyl) -4,6-dinitromethylbenzimidazole (I-25) 1- (4-chloro-2-nitrobenzyloxycarbonyl) -4,6-dinitrobenzimidazole (I-26) N- (4-nitro (Benzyloxycarbonyl) benzimidazole (I-27) 1- (2-nitrobenzyloxycarbonyl) -4-
Phenylbenzimidazole (I-28) 1- (2-nitrobenzyloxycarbonyl) -4-
Butylbenzimidazole (I-29) 1- (5-butyl-2-nitrobenzyloxycarbonyl) -4-methylbenzimidazole (I-30) 1- (5-phenyl-2-nitrobenzyloxycarbonyl) -4- Methylbenzimidazole

Specific examples of the N, N'-carbonyldibenzimidazole derivative represented by the general formula (II) of the present invention include the following compounds. Among them, those in which the substituents in the general formula (II) are R3 = R6 and R4 = R5 are easier to synthesize. (II-1) N, N'-carbonyldibenzimidazole (II-2) carbonyl-1,1'-bis (4-methylbenzimidazole) (II-3) carbonyl-1,1'-bis (5-methyl) Benzimidazole) (II-4) carbonyl-1,1'-bis (4-butylbenzimidazole) (II-5) carbonyl-1,1'-bis (5-butylbenzimidazole) (II-6) carbonyl- 1,1′-bis (4-methoxybenzimidazole) (II-7) carbonyl-1,1′-bis (5-methoxybenzimidazole) (II-8) carbonyl-1,1′-bis (4-chloro) Benzimidazole) (II-9) carbonyl-1,1'-bis (5-chlorobenzimidazole) (II-10) carbonyl-1,1'-bis (4-cyanobenzimidazole) (II-11) carbonyl- 1,1′-bis (5-cyanobenzimidazole) (II-12) carbonyl-1,1′-bis (4- Nitrobenzimidazole) (II-13) carbonyl-1,1'-bis (5-nitrobenzimidazole) (II-14) carbonyl-1,1'-bis (4-phenylbenzimidazole) (II-15) carbonyl -1,1'-bis (5-phenylbenzimidazole) (II-16) carbonyl-1,1'-bis (4,5-dimethylbenzimidazole) (II-17) carbonyl-1,1'-bis ( 4,6-dimethylbenzimidazole) (II-18) carbonyl-1,1′-bis (4,7-dimethylbenzimidazole) (II-19) carbonyl-1,1′-bis (5,6-dimethylbenzo) Imidazole) (II-20) carbonyl-1,1′-bis (4,5-dimethoxybenzimidazole) (II-21) carbonyl-1,1′-bis (4,7-dimethoxybenzimidazole) (II-22) ) Carbonyl-1,1'-bis (4,5-dichlorobenzimidazole) (II-23) Carbonyl-1,1'-bis (4,7-dichlorobenzimidazole) (II-24) carbonyl-1,1'-bis (4,5-dicyanobenzimidazole) (II-25) carbonyl-1,1 ' -Bis (4,7-dicyanobenzimidazole) (II-26) carbonyl-1,1'-bis (4,5-dinitrobenzimidazole) (II-27) carbonyl-1,1'-bis (4,7 -Dinitrobenzimidazole) (II-28) carbonyl-1- (4-methylbenzimidazole) -1 '-(7'-methylbenzimidazole) (II-29) carbonyl-1- (4-nitrobenzimidazole)- 1 '-(7'-nitrobenzimidazole) (II-30) carbonyl-1- (4,5-dimethylbenzimidazole) -1'-(6 ', 7'-dimethylbenzimidazole) (II-31) carbonyl -1- (4,5-dinitrobenzimidazole) -1 '-(6', 7'-dinitrobe Zone imidazole)

Typical epoxy compounds used as the main component of the curable resin composition of the present invention include glycidyl ether type epoxy resins such as bisphenol A and epichlorohydrin which are reacted in the presence of an alkali. Bisphenol A epoxy resin, epoxidized resin obtained by condensation reaction of bisphenol A and formalin, epoxy resin obtained by using brominated bisphenol A instead of bisphenol A, or novolak resin obtained by reacting novolak resin with epichlorohydrin to form glycidyl ether Epoxy resins, for example, phenol novolak type, ortho-cresol novolak type, epoxy resin such as pt-butylphenol novolak type,
There are bisphenol F type epoxy resin, bisiphenol S type epoxy resin, etc. obtained by reacting epichlorohydrin with bisphenol F or bisphenol S. Further, a cycloaliphatic epoxy resin having a cyclohexene oxide group, a tricyclodecene oxide group, a cyclopentene oxide group, etc .; diglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl terephthalate Glycidyl ester resins such as ester, diglycidyl-p-oxybenzoic acid and glycidyl dimer acid; tetraglycidyl diaminodiphenylmethane, triglycidyl-p-aminophenol, diglycidyl aniline, diglycidyl toluidine, tetraglycidyl metaxylylenediamine, diglycidyl Glycidylamine-based resins such as tribromoaniline and tetraglycidylbisaminomethylcyclohexane; Bixylenol type or biphenol type epoxy resins; triglycidyl isocyanurate having a triazine ring; Ntoin type epoxy resin is a copolymer having pendant glycidyl groups, but not limited thereto. These can be used alone or in combination of two or more.

The curable composition of the present invention can be obtained by mixing an appropriate amount of the above-mentioned epoxy compound with the above-mentioned benzimidazole derivative represented by the general formula (I). Specifically, for each mole of epoxy group in the epoxy compound,
0.1 to 30 mol%, preferably 1 to 10 mol%, and more preferably 3 to 5 mol%. Preparation of the composition depends on the properties of the epoxy compound used (solid-liquid)
Can be carried out simply by mixing a benzimidazole derivative and an epoxy compound, and if necessary, dimethylformamide (hereinafter abbreviated as DMF), tetrahydrofuran (hereinafter abbreviated as THF),
Mixing can also be performed using a suitable solvent such as methyl ethyl ketone and ethyl acetate.

The prepared composition is applied on a substrate and cured by light irradiation and heating. Light sources for light irradiation for releasing benzimidazoles from benzimidazole derivatives include industrially usable light sources such as low-pressure mercury lamps, high-pressure mercury lamps, xenon lamps, metal halide lamps, laser beams, electron beams, and X-rays. Any of the known active light sources can be used. The irradiation time varies depending on the light intensity of the light source, and is as short as 5 minutes and as long as about 3 hours, but generally about 30 to 6 hours.
0 minutes. By such light irradiation, the benzimidazoles are liberated from the benzimidazole derivative as in the above reaction formula, and function as a catalyst for ring-opening polymerization of the epoxy group of the epoxy compound incorporated in the composition. After light irradiation, the curable composition is heated to about 80 to 200 ° C., preferably about 100 to 200 ° C.
By heating to 160 ° C., heat curing is performed smoothly in a short time, and a compound having excellent curing characteristics is obtained.

According to another aspect of the present invention, a polyfunctional phenol compound, a polyfunctional carboxylic acid, an acid anhydride or an amine compound is further added to the benzimidazole derivative and the epoxy compound. In such a cured composition, the benzimidazole derivative releases the benzimidazole by light irradiation as described above, and this acts as a catalyst for the addition reaction of the epoxy compound with the compound as described above. Curing gives a cured product with excellent properties.

The polyfunctional phenol compound used in the present invention includes 4,4 ', 4 "-methylidene trisphenol, bisphenol A, bisphenol F, bisphenol S, phenol resin, cresol resin and the like. It is not limited.

Examples of polyfunctional carboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid, fumaric acid, itaconic acid, muconic acid, phthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid,
3-ethylhexahydrophthalic acid, 4-ethylhexahydrophthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid,
Examples include, but are not limited to, 3-ethyltetrahydrophthalic acid, 4-ethyltetrahydrophthalic acid, trimellitic acid, and the like.

Typical acid anhydrides include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, and endo-anhydride. Dibasic anhydrides such as methylenetetrahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, chlorendic anhydride, and methyltetrahydrophthalic anhydride; aromatics such as trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride Group polycarboxylic acid anhydrides; and other accompanying compounds such as 5- (2,5-
Examples include, but are not limited to, polycarboxylic anhydride-derived derivatives such as dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride.

As the amine compound, 4,4 ′,
4 "-triaminotriphenylmethane, 4,4 ', 4"
-Triaminotriphenylethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, o-, m-, p-phenylenediamine, boron trifluoride-amine complex (complex), dicyandiamide and the like Derivatives, organic acid hydrazide, diaminomaleonitrile, melamine and its derivatives, amine imides, salts of polyamines, and the like, but are not limited thereto.

The above-mentioned polyfunctional phenol compounds, carboxylic acids, acid anhydrides and amine compounds can be used alone or in combination of two or more. The amount of the phenol group, the carboxyl group, or the amino group is theoretically equal to 1 mol of the epoxy group of the simultaneously compounded epoxy compound. The range is suitably from 1.3 to 1.3 mol, preferably from 0.3 to 1.1 mol.

Even in a curable composition comprising an imidazole derivative, an epoxy compound and the above-mentioned polyfunctional phenol compound, carboxylic acid, acid anhydride, or amine compound, the amount of the imidazole derivative, the method of adjusting the composition,
The light source for light irradiation, the time, and the heating temperature are the same as the conditions applied to the curable composition comprising the imidazole derivative and the epoxy compound, whereby a cured product having excellent curing properties is obtained. In addition, the curable composition of the present invention may further contain, if necessary, barium sulfate, silicon oxide, talc, clay, calcium carbonate, or any other commonly used filler within a range that does not impair the photoreactivity or the thermosetting reaction described above. And various additives such as known and commonly used coloring pigments such as phthalocyanine blue, phthalocyanine green, titanium oxide and carbon black, defoamers, adhesion promoters and leveling agents.

[0030]

[Synthesis Example 1]

Synthesis of N, N'-carbonyldibenzimidazole Benzimidazole (hereinafter abbreviated as BI) 11.81
g (0.100 mol) in 380 ml of anhydrous THF, and then 2.47 g of phosgene gas at 15 to 20 ° C. with stirring.
(0.025 mol) was introduced over 10 minutes. After stirring was continued for 30 minutes and disappearance of phosgene was detected on a detection paper, benzimidazole hydrochloride generated by the reaction was removed by filtration. Next, THF was distilled off under reduced pressure from the filtrate, 50 ml of anhydrous toluene was added to the obtained solid, and the mixture was well dispersed, followed by filtration and vacuum drying to obtain 5.57 g of the desired product.
Since the melting point was 182 to 184 ° C., it was described in the literature.
82-183 ° C, (Ann. Chem., 612 <1958> 187-19
2), the compound was identified as N, N'-carbonyldibenzimidazole;

Synthesis Example 2 Synthesis of N- (2-nitrobenzyloxycarbonyl) benzimidazole (hereinafter abbreviated as 2NBCBI) 1.836 g of N, N'-carbonyldibenzimidazole
(7 mmol) was dissolved in 30 ml of DMF.
1.072 g (7 mmol) of nitrobenzyl alcohol
Was dissolved in 12 ml of DMF and added dropwise using a dropping funnel, and 0.071 g (0.7%) of triethylamine was used as a catalyst.
Mmol), and the reaction was carried out at room temperature for 8 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate, washed four times with distilled water, dried over anhydrous magnesium sulfate, and the ethyl acetate was distilled off under reduced pressure. The obtained solid was recrystallized once using a mixed solvent of ethyl acetate and n-hexane to give a melting point of 11
1.575 g (76% yield) of the target product having a temperature of 5.3 to 115.9 ° C was obtained. IR spectrum of this product and ¹
The H-NMR spectrum is shown below. IR spectrum (KBr, cm ^-1 ): 1753 (C =
O), 1525 and 1341 (NO ₂ ), 1171 and 1062 (C—O—C) ¹ H-NMR spectrum (200 MHZ, solvent CDCl
₃ , internal standard TMS): δ (ppm) = 5.93 (s,
2.0H, CH2O), 7.37-7.43 (m, 2.
0H, aromatic), 7.50-7.91 (m,
4.0H, aromatic), 8.01-8.12.
(M, 1.0H, aromatic), 8.19 (d,
1.0H, aromatic), 8.49 (s, 1.0
H, N-CH = N) product elemental analysis: calculated for _{C 15 H 11 N 3 O 4} : C; 60.61
%, H; 3.73%, N; 14.14% Analytical value: C; 60.89%, H; 3.68%, N; 1
4.26% The above analysis results indicate that 2NBCBI is formed. Also, from the result of the differential thermal analysis, 2NBCBI
Was 205 ° C.

[Synthesis Example 3] N- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) benzimidazole (hereinafter referred to as DMNBCB)
Synthesis of N, N'-carbonyldibenzimidazole 1.836 g
(7 mmol) was dissolved in 30 ml of DMF.
5-dimethoxy-2-nitrobenzyl alcohol 1.4
92 g (7 mmol) was dissolved in DMF (12 ml) and added dropwise using a dropping funnel. 0.071 g (0.7 mmol) of triethylamine was added as a catalyst, and the reaction was carried out at room temperature for 8 hours. After completion of the reaction, the reaction mixture was diluted with chloroform, washed four times with distilled water, dried over anhydrous magnesium sulfate, and chloroform was distilled off under reduced pressure. The obtained solid was recrystallized once using ethyl acetate to give a melting point of 18%.
2.051 g (82% yield) of the target product having a temperature of 1.1 to 181.6 ° C. was obtained. IR spectrum of this product and ¹
The H-NMR spectrum is shown below. IR spectrum (KBr, cm ^-1 ): 1752 (C =
O), 1521 and 1328 _(NO 2), 1172 and ^{1068 (C-O-C)} 1 H-NMR spectrum (200MHZ, solvent CDCl
₃ , internal standard TMS): δ (ppm) = 3.97 (s,
_{6.0H, CH 3 O), 5.90} (s, 2.0H, CH
2O), 7.09 (s, 1.0H, aromati
c), 7.37 to 7.44 (m, 2.0H, aroma
tic), 7.76 to 7.82 (m, 2.0H, aro)
magnetic), 7.98-8.06 (m, 1.0H, a
romantic), 8.47 (s, 1.0 H, N-CH)
= N) product elemental analysis: calculated for _{C 17 H 15 N 3 O 4} : C; 57.14
%, H; 4.23%, N; 11.76% Analysis: C; 57.28%, H; 4.32%, N; 1
1.44% The above analysis results indicate that DMNBBCBI is formed. Also, from the results of the differential thermal analysis, it was found that DMNBC
The decomposition temperature of BI was 201 ° C.

Example 1 2NBC obtained in Synthesis Example 2
0.60 g (2 mmol) of BI was added to an epoxy resin (Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 18).
6) The curable composition was prepared by mixing with 3.72 g (20 mmol as epoxy group). This was applied to a KBr plate, and a 250 W ultra-high pressure mercury lamp (illuminance: 10.0 mW / cm
² , 254 nm) for a predetermined period of time, followed by heating at 120 ° C. to determine the epoxy group reaction rate by IR.
Tracked by measuring the spectrum.

Comparative Example 1 Epoxy resin (Epicoat 8)
28) 0.24 g (2 mmol) of BI was mixed with 3.72 g (20 mmol as epoxy group), heated at 120 ° C., and the reaction rate of the epoxy group was measured in the same manner as in Example 1.

FIG. 1 shows the results of measurement of the reaction rate of the epoxy group by IR spectrum analysis obtained in Example 1 and Comparative Example 1. As is clear from these results, free benzimidazole generated from 2NBCBI by light irradiation promoted ring-opening polymerization of the epoxy group. Comparative Example 1
The results were equal to or higher than those obtained when the direct benzimidazole was added. Further, all the compositions on the KBr plate after heating for 120 minutes were cured well, and insoluble cured products were produced.

Example 2 DMNB obtained in Synthesis Example 3
A curable composition was prepared by mixing 0.60 g (2 mmol) of CBI with 3.72 g (20 mmol as epoxy group) of an epoxy resin (Epicoat 828). This is KB
r plate, and a 250 W ultra-high pressure mercury lamp (illuminance: 10.0
(mW / cm ² , 254 nm), followed by heating at 120 ° C. for 120 minutes, and the reaction rate of the epoxy group was tracked as in Example 1. as a result,
It was confirmed that 65% of the epoxy groups had reacted.
Further, all the compositions on the KBr plate after heating for 120 minutes were cured well, and insoluble cured products were produced.

Example 3 2NBC obtained in Synthesis Example 2
0.30 g (1 mmol) of BI was added to 1.8 g of phenol novolak type epoxy resin (DEN438 manufactured by Dow Chemical Company, epoxy equivalent: 181) (10 as an epoxy group).
Mmol) to prepare a curable composition. This was applied to a KBr plate, and a 250 W ultra-high pressure mercury lamp (illuminance: 1
0.0 mW / cm ² , 254 nm), and then subjected to 60 spectral irradiations, followed by heating at 120 ° C. for 120 minutes.
The reaction rate of the epoxy group was tracked in the same manner as in Example 1. As a result, it was confirmed that 65% of the epoxy groups had reacted. Further, all the compositions on the KBr plate after heating for 120 minutes were cured well, and insoluble cured products were produced.

Example 4 2NBC obtained in Synthesis Example 2
0.60 g (2 mmol) of BI was glycidylamine type
Poxy resin (Sumieoxy manufactured by Sumitomo Chemical Co., Ltd., Epoxy
2.4 g (20 equivalents as epoxy group)
Mol) to prepare a curable composition. This is KB
r plate, and a 250 W ultra-high pressure mercury lamp (illuminance: 10.0
mW / cm ²254 nm) for 60 spectral irradiations
Then, heating was performed at 120 ° C. for 120 minutes.
The reaction rate of the epoxy group was tracked in the same manner as in Example 1. as a result,
It was confirmed that 80% of the epoxy groups had reacted.
Further, the composition on the KBr plate after 120 minutes of heating was
In all cases, curing proceeded well, and an insoluble cured product was formed.

Example 5 2 obtained in Synthesis Examples 2 and 3
NBCBI, DMNBBCBI, and BI and 2-nitrobenzyloxycarbonylimidazole (hereinafter NBCBI)
I) was mixed in an amount of 5 mol% with respect to the epoxy group of Epicoat 828 to prepare a curable composition. Store the curable composition in the dark at room temperature,
The reaction rate of the epoxy group was followed by the spectrum.

FIG. 2 shows the epoxy group reaction rate of the curable composition when stored at room temperature and in a dark place. As is clear from FIG.
BI and NBCI gelated due to the reaction of the epoxy group and could not be stored for one month, whereas 2NBBCBI
And that the storage stability of DMNBBCBI is very excellent.

[0041]

The curable resin composition of the present invention has a storage stability in a dark place which is lower than that of BI itself or NBCI by using a derivative in which an amino group of a benzimidazole is blocked as a curing catalyst for an epoxy resin. It is possible to obtain a curable resin composition having excellent properties. In addition, benzimidazoles are released by light irradiation to act as a catalyst, and then a thermosetting reaction is performed, whereby a cured product having excellent curing properties can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the heating time of the compositions obtained in Example 1 and Comparative Example 1 and the conversion of epoxy groups.

FIG. 2 is a graph showing the relationship between the elapsed time of the composition obtained in Example 5 during storage at room temperature and in a dark place and the reaction rate of an epoxy group.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Shigeru Shimada 1-1-1, Fukukawa-Minamicho, Shinnanyo-shi, Yamaguchi Prefecture Inside the Nanyo Plant of Hodogaya Chemical Industry Co., Ltd. (72) Tadaomi Nishikubo 3-6-1 Motofujisawa, Fujisawa-shi, Kanagawa Prefecture No. 8 (72) Inventor Atsushi Kameyama 1-3-10-705 F-term (Reference) 1-10-3 Nishi-Kanagawa, Kanagawa-ku, Yokohama-shi, Kanagawa 4H039 CA65 CD10 CD90 4J036 AD08 AD21 AF06 AF08 AF19 AF23 AG01 AG06 AG07 AH07 AJ02 AJ09 AJ17 AJ18 AK15 DB15 DC02 DC40 FB07 GA26 HA02 JA01 JA06 JA07 JA09

Claims (5)

[Claims] 1. A benzimidazole derivative represented by the following general formula (I). Embedded image (Wherein R 1 and R 2 may be the same or different and each represents a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a propyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-
Butyl, pentyl, hexyl, alkyl (7 or more carbon atoms), alkoxy, alkenyl, cyano,
A nitro group, a phenoxy group, an aralkyl group or an aryl group, R1 and R2 may combine to form a ring, and a plurality of these rings may form a condensed ring;
4, R5 and R6 may be the same or different and include a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a propyl group,
n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, alkyl (7 or more carbon atoms) group, alkoxy group, alkenyl group, cyano group, nitro group, phenoxy group, aralkyl group Or, it represents an aryl group, and each of R3, R4, R5 and R6 may combine to form a ring, or a plurality of these rings may form a condensed ring. ) 2. A composition comprising (A) a benzimidazole derivative represented by the following general formula (I), which produces free benzimidazoles by light irradiation, and (B) a polyfunctional epoxy compound. Curable composition. Embedded image (Wherein R 1 and R 2 may be the same or different and each represents a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a propyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-
Butyl group, pentyl group, hexyl group, alkyl (7 or more carbon atoms) group, alkoxy group, alkenyl group, cyano group,
A nitro group, a phenoxy group, an aralkyl group or an aryl group, R1 and R2 may combine to form a ring, and a plurality of these rings may form a condensed ring;
4, R5 and R6 may be the same or different and include a hydrogen atom, a halogen atom, a methyl group, an ethyl group, a propyl group,
n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, alkyl (7 or more carbon atoms) group, alkoxy group, alkenyl group, cyano group, nitro group, phenoxy group, aralkyl group Or, it represents an aryl group, and each of R3, R4, R5, and R6 may combine to form a ring, or a plurality of these rings may form a condensed ring. ) 3. (A) a benzimidazole derivative represented by the general formula (I), which generates free benzimidazoles by light irradiation, (B) a polyfunctional epoxy compound, and (C) a polyfunctional compound A curable composition comprising at least one compound selected from the group consisting of phenol compounds, polyfunctional carboxylic acids, acid anhydrides and amine compounds. 4. The benzimidazole derivative represented by the general formula (I) is one or more selected from the following compounds (I-1) to (I-30). 2
Or the curable composition according to claim 3. (I-1) N- (2-nitrobenzyloxycarbonyl) benzimidazole (I-2) N- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) benzimidazole (I-3) N- (5- Methyl-2-nitrobenzyloxycarbonyl) benzimidazole (I-4) N- (4-chloro-2-nitrobenzyloxycarbonyl) benzimidazole (I-5) N- (3-nitrobenzyloxycarbonyl) benzimidazole ( I-6) 1- (2-Nitrobenzyloxycarbonyl) -4-
Methylbenzimidazole (I-7) 1- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) -4-methylbenzimidazole (I-8) 1- (5-methyl-2-nitrobenzyloxycarbonyl)- 4-methylbenzimidazole (I-9) 1- (4-chloro-2-nitrobenzyloxycarbonyl) -4-methylbenzimidazole (I-10) 1- (2-nitrobenzyloxycarbonyl) -4-
Nitrobenzimidazole (I-11) 1- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) -4-nitrobenzimidazole (I-12) 1- (5-methyl-2-nitrobenzyloxycarbonyl)- 4-nitrobenzimidazole (I-13) 1- (4-chloro-2-nitrobenzyloxycarbonyl) -4-nitrobenzimidazole (I-14) 1- (2-nitrobenzyloxycarbonyl) -5-
Methylbenzimidazole (I-15) 1- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) -5-methylbenzimidazole (I-16) 1- (5-methyl-2-nitrobenzyloxycarbonyl)- 5-Methylbenzimidazole (I-17) 1- (4-chloro-2-nitrobenzyloxycarbonyl) -5-methylbenzimidazole (I-18) 1- (2-nitrobenzyloxycarbonyl) -5-
Nitrobenzimidazole (I-19) 1- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) -5-nitrobenzimidazole (I-20) 1- (5-Methyl-2-nitrobenzyloxycarbonyl)- 5-nitromethylbenzimidazole (I-21) 1- (4-chloro-2-nitrobenzyloxycarbonyl) -5-nitrobenzimidazole (I-22) 1- (2-nitrobenzyloxycarbonyl) -4,
5-dimethylbenzimidazole (I-23) 1- (4,5-dimethoxy-2-nitrobenzyloxycarbonyl) -4,5-dimethylbenzimidazole (I-24) 1- (5-methyl-2-nitrobenzyl (Oxycarbonyl) -4,6-dinitromethylbenzimidazole (I-25) 1- (4-chloro-2-nitrobenzyloxycarbonyl) -4,6-dinitrobenzimidazole (I-26) N- (4-nitro (Benzyloxycarbonyl) benzimidazole (I-27) 1- (2-nitrobenzyloxycarbonyl) -4-
Phenylbenzimidazole (I-28) 1- (2-nitrobenzyloxycarbonyl) -4-
Butylbenzimidazole (I-29) 1- (5-butyl-2-nitrobenzyloxycarbonyl) -4-methylbenzimidazole (I-30) 1- (5-phenyl-2-nitrobenzyloxycarbonyl) -4- Methylbenzimidazole 5. A compound of the general formula (I) which is an intermediate for synthesizing a benzimidazole derivative represented by the general formula (I)
N, N'-carbonyldibenzimidazole derivatives represented by I). Embedded image (Wherein, R3, R4, R5, and R6 are the same as defined above.)